Tool coupling systems and spindle connector assemblies configured for use with interchangeable cutting or machining tools provide a number of process efficiencies. A smaller number of machine spindles can be used for a larger variety of machine operations, and downtime between various cutting tasks can be reduced by decreased need to switch apparatus for each machining application. In order to realize the foregoing efficiencies, tool holder assemblies and spindle connector assemblies must be capable of secure connection with minimal tool change downtime and reduced operator effort to secure the tool head. As tool diameter increases, the architecture necessary to maintain a secure connection with minimal tool change downtime often results in a greatly increased machine footprint. Such disadvantages can be difficult to address, either singly or in tandem. Therefore, there exists a need for improved tool holder assemblies and methods of using the same.